Mechanism for truing and dressing grinding wheels



1932- F. J. HOHNHORST ET AL 1,340,718

MECHANISM FOR TRUING AND DRESSING GRINDING WHEELS Filed April 20. 1929 2 Sheets-Sheet 7 m M6 7 M a N Mb E w... m a W bl: L flw slll hww fi m w w NW Z w 8 1i 1 n v m 7/ L V A o 6 v h. l e \(V 3 CH Jan. 12, 1932. F. J. HOHNHORST ET AL 1,840,718

MECHANISM FOR TRUING AND DRESSING GRINDING WHEELS Filed April 20, 1929 2 Sheets-Sheet 2 IDIY Patented Jan. 12, 1932 nan-r51 1) .TATEs P ENT O E FERDINAND J. nonmiozasr AND FERDINAND J. KROEGER, F covme'roiv; KENTUCKY 'MEcnANIsM FOR TRUING Ann nnnssnve GRINDING w'HnELs Application filed April 20,

Our invention relates to mechanism for truing and dressing grinding wheels, such as emery wheels, employed in machinery'for grinding or polishing surfaces of metal in precision grinding.

An example of mechanism of this character is shown and described in Patent .No. 1,544,985, granted us on July7, 1925, for mechanism for truing and dressing grinding 19 wheels.

The grindingwheels employed in grinding metals and similar hard substances,.which it is the object of our improved device to operate on, are composite inding wheels con taining comminuted or nelydivided emery, carborundum or other cutting mediumand a suitable bond, suitably bound together as a composite mass; the fineness of the grains of the cutting medium being determined by the coarseness or fineness of the grinding which is to be done. i

It is essential in precision grinding that the grinding wheels shall be maintained in their true form, for instance cylindrical form.

It is the object of our invention to provide novel means for truing ordressing the grinding surface of the grinding wheel; further, to provide a composite abra'ding bar and means whereby to present the abrading bar to the grinding surface of the grinding wheel; further, to provide means for traverse between said abrading bar and said grinding surface for cleaning and sharpening said grinding surface by means of said abrading bar; further, to provide a composite abrading bar having a texture harder and coarser than the texture of the grinding wheel on which it acts, and to provide a composite abrading bar containing grains of emery, carborunclum or, other cutting .med1um,

V which are harder and coarser than the grains ant to disturbance or to release of the grains of the cutting mediums in the grinding wheel, and suitably bound together 'bya' suitable bond in suitable manner," to form the composite structure of the abrading bar, the bond in the abrading bar being more resistof cutting mediums therein-than is the'bon'd in. the grinding wheel, so as to provide an abradingbarwhich is more resistant to wear 'ter:

1929. Serial No.3 56,806.

than the grinding wheel and which has a N cutting action on the grindingwheel.

It the object of our invention further to provide novel ,means for supporting the abrading bar for presentingth'e' same endwise to' the grinding surface of the grinding wheel and'novel means whereby to os-. cillate said abrading bar for causing its end to traverse the grinding surface'of the grinding wheel in opposite directions to clean and sharpen said grinding surface.

' Itis the object of our invention further to provide a plurality of abrading barsarfor individual and simultaneousaction on said grinding surface.

The invention will be further readily understood from the following description and claims, and from the drawings, in which lat- Fig. 1 is a side elevation of our improved device, mounted in a grinding machine, and showing power means for oscillating the abrading bar, the grinding machine being shown partly'in section and partly broken away. 7

Fig. 2 is' a plan view of our improved device. r

Fig. 3 is aside elevation of our improved device, showing manual'means for oscillating the abrading bar. p

F ig. 4 is a cross-section of our. improved device,-taken.on the line l4.of Fig. 1.

- Fig; 5' is a cross-section of the same, taken in the plane of the line 5-5, of Fig. 4, V

.FigPG is a perspective view showing an...

abrading bar comprising spaced nested individual abrading bars; 7 Fig. '7 is a cross-section of thesame, taken on the line 7.7' of Fig. 6; and, 1 a Figs. 8,- 9 andglO are perspective-views, showing ab-rading'z bars comprising spaced Vidual abrading' bars to the grindingwheel V nested individual abrading bars of other cross-sectional forms and arrangements.

The grinding machine may be of any desired kind, and may for instance comprise a frame 11, on which there is a slide 12, adjustable in suitable manner upon the frame, and supporting a grinding wheel 13 in suitable bearings on the slide. The grinding wheel is instanced as rotating in the direction of the arrow a. 1 The grinding wheel 18 is in practice a cgmposite grinding wheel, comprising grains or emery, carborundum or other cutting medium of the desired degree of coarseness or fineness, depending on the coarseness or fineness 'of the grinding which is to be performed, the grains of cutting medium being bound together by a suitable bond in suitable manner or by suitable process for forming a hard composite grinding wheel.

A saddle 14 is slidable on guideways 15, 16, on the frame, and is operable by means of a rack 1?, with which a pinion 1 suitably driven, meshes, for providing suitable endwise feed between the work or the abrading bar 19 and the grinding wheel 13, although this endwise feed may be obtained by endwise movement of the grinding wheel with relation to the work or the abrading bar. Such election of end wise feed of the Work or the grinding wheel is explained in our afore said patent.

The work-supporting table 21 is pivoted by a pivot 22 on the saddle 14:. This worle supporting table has thereon the usual head center and tail center, between which the work is supported, as explained in our aforesaid patent.

The abrading bar contains grains of emery, carborundum or other cutting medium which are harder and coarser than the grains of cutting medium in the emery wheel on which the abrading bar acts, and the texture of the abrading bar is harder than the texture of the grinding wheel on which the abrading bar acts.

The abrading bar is a composite bar comprising such harder and coarser grains and a suitable bond bound. together as a com posite mass in suitable manner or by suitable process and forming a composite mass hav ing a texture harder and coarser than the texture of the grinding wheel.

The abrading bar is shown presented with its end toward the grinding surface of the grinding wheel. It is preferably of quite large cross-sectional area, so that a protrud ing end of an abrading bar may successfully withstand the side stresses to which the abrading bar-is subjected in the truing or dressing operation upon the grinding wheel.

The grinding wheel during operation becomes impregnated with particles of dust. dirt or metal from the work being operated on, and becomes comparatively glossy, and

thereby loses its grinding effect, its granular structure also becoming dull at the grinding face, thereby reoucing its grinding or polish ing properties.

The abrading bar acts to remove such particles of dust, dirt and metal out of the grinding wheel, and to roughen and sharpen the granular structure of the grinding face. The abrading bar further acts upon said grinding face in opposite directions by moving thereover in opposite directions, frictionally acting on the dirt and particles of metal and other foreign substances in the interstices of said grinding surface in opposite directions to dig out such foreign substances and to more effectively sharpen the grains of the granular structure of said grinding surface. 7

The abrading bar is oscillated for the purpose. T ie abrading bar is shown supported in a holder 25, which is provided with a channel 26, which extends through the body 27 of the holder and in which the abrading bar is received. A clamp-plate 28 is clamped upon the abrading bar by means of bolts 29, received through holes 80 in the clamp-plate and into threaded holes 31 in the body.

The abrading end 35 of the abrading bar extends from the holder toward the grinding wheel; tend rearwardly out of the holder, as indicated by the rearwardly extending end 36 thereof. The abrading bar may from time to time be adjusted lengthwise in the holder as the 'abrading end thereof is shortened by wear.

A stub 41 extends from a bracket 42, the holder beingshown pivotally mounted on the stub. This pivotal mounting is shown by means of ball-bearings 43, a l, received about the stub in recess 45 in the holder. The ball-bearings are preferably oppositely disposed radial and end thrust ball-bearings. The inner raceways l6 of the ball-bearings are positioned in separated relation by a collar 17 fixed as by pins 50, on the stub. The outer raceways 48 of the ball-bearings are separated by a bushing 49 in the recess. The outer raceways with the bushing therebetween are clamped in the recess by means of a plug 51, screwed into a threaded recess 52 in the holder, against an annular shoulder 53. The abrading bar is thus pivot-ally mounted, and the holder is securely held laterally on the stub. 1

he stub is ad'ustable on the, bracket, as by having its shank 55 received in a slot 56 in the bracket. The opposite sides of the shank, which'coact with the sides of the walls of the slot, are flattened as at 5 1. There is a collar 57 at one end of the shank, a nut 58 is threaded over the threaded reduced end 59 at the other end of the shank, and clamps the shank to the bracket between the collar and a-washer 6O clamped by the nut.

The abrading bar may also ezz- I The bracket is-se'c'uredto'ithe table 21.

The bracket is provided-with an arm 61 which threaded stud 67 extends fronrthej bracket through a'hole, in the clamp-piece and has a clamping nut 68 threaded thereover, for clamping the bracket to the table at. desirable points-along the rail. r e

The holder of the abrading bar is arranged to be oscillated for causing traverse between the end of the abrading bar and the grinding wheel. The abrading end-face of the abrading bar is shown formed on an are described from the axis of the stub'as its center. The traversing movement isshown asin the direction of the planeof the-grinding wheel but may be at any angle thereto. 1

Automatic means for oscillating the abrading bar may be provided and an example of same is shown in Figs. 1 and'2. 7 f

In this form a shank 71 extends from the holder 25, being shown screw-threaded at 7 2 to the clamp-plate'28. ''An electric motor'73 isfixed on the bracket. A worm'i' l ison the motor shaft, and meshes with1a wormwheel 75. The worm-wheel is on a shaft 76 journaled in abearing 77 on thebracket, and has a crank-wheel 78thereon, provided with a crank-pin 79. j One end of a link 80is articulated at 81 with the shank 71. V The, link provided with a fork 82 at'its other end,received over the crank-pin 79. y v

The'link may be disconnected from its source of power when .it is desired to place the abradingbar out of use- This is accomplished by providing said fork for permitting ready release between the operating end of the link and the crank-pin.

The link is provided with a handle 85, by which itmay be raised so as to move the walls of the slot in the fork away from the crank-pin, and, for instance, place the fork about a pin 86 on a bracket 87 extendingfrom the bearing 7 7. The holder for-the abrading bar is thus swung rearwardly .on its pivot for swinging the abrading end of the abrading bar upwardly out of range withthe grinding wheel. 'If it is desired toagain operate the abrad'ing bar, the link is released from the pin 86 and again connected with the crank-pin 79. i-M ,1. r

- When the shank isadjusted inthe slot 56, it is desirable to also adjust'the power connection so that the relationfof the abrad ing end 35t0 the grinding wheel is maintained. This is shown accomplished by :ad justing the length of thelink 80, as by-adjusting the fork 82 lengthwise of the. link. Thus the fork is provided with ashank 88. A' clamp-bolt 89 extends through a 510 590. in the'link,.and isthreadedin the-shank A handle is 'yieldingly held therein; M

The abrading bar may comprise a; series pin 95 on theshank is slidable ins-slot 96 in the-link for maintaining the linkand shank parallel.

Manual means are shown in Fig. 3- for oscillating the abrading bar. These are shown consisting of a shank 91 extendingfrom theholder, being secured to theholder by a threaded connection 92 with the clampplate 28, the shank having a handle 93 extended therefrom, by means of which the holderfor the abrading bar maybe oscillated for back and forth traverse the abrading faceofthe abrading bar crosswise-of the abrading surface of the abrading wheel.

-If it is desired to place the abrading bar out of use.' the holder 25 isswung on its pivotand the handle 93 is connected with-a latch 9lextendingfrom the bracket. This latch is a resiliently, yielding latch, and the of nested individual abrading bars which extend parallel with each other in nested relation, and preferably spaced apart, so as to provide a: greater nuinber of abrading.

edges-for the abrading bar. These individual abradingbarsmay be of various forms and nested in various relations, and we have in Figs. 6. to;.10 inclusive shown various crosssectional forms and arrangements of such nested individual abrading bars.

Beferringto Figs. .6 and'7, the abrading bar is'shown composed of a nest of series of individual abrading bars 101, which are shown square in cross-sectiomthe individual abrading bars being separated by separating strips 102, 103, for spacing said individual abrading bars apart in order to present an increased number of abrading'fedges to the grinding surface of thegrinding wheel. I

.This series ofindividual abrading bars,

ido

its

which compose the abrading bar proper, all

act on the abrading surface, and have an end abrading face, which is collectively on the individual abradinglbars, in the form of an are described from the pivotalaxis of the holder. All these individual abrading bars act individually and collectively on the grinding surface of. the grinding wheel. The individual abrading bars are shifted iio lengthwise in the holdeifto take up' wear. I

with their abrading end-maintained .in 'arcu; aterelation.v Theseries or nest ofindividual abrading b'arsare clamped in the holder in the same manner in which the integral abradingbar 19 is clamped. V 7' Fig.8 representsa series of-individual abrading bars which are rectangular in cross-section and are arranged side by side,

having spacingstrips 2106 between them. 7

This series or nest. of individual abrading' bar's {is clamped in the holder in manner similar to the integral abrading bar The abrading endof the nest ofabrading 1? also formedon the arc of a circle having the pivotal axis of the holder as its center.

In Fig. 9 a series of individual abrading bars 111, 112, 113, are shown, which areof irregular cross-sectional form and have spacing strips 11 1 therebetween. These individual abrading bars comp-rise slanting abrading edges 115. This nest of individual abrading bars also has its abrading end on a similar arc to the other forms shown. The nest of individual abrading bars are clamped in the holder in manner similar to the other abrading bars shown and described.

Fig. 10 represents a nest of individual abrading bars 118 rectangular in cross-section, spaced apart by spacing strips 119, and presented fiatwise to the grinding surface of the grinding wheel. The nest of individual abrading bars is clamped in the holder in manner similar to the other abrading bars shown and described. The abrading end of this nest of abrading'bars is also shown on a similar arc.

The individual abrading bars of? the respective forms may be adjusted lengthwise along the spacing strips and in the holder to take up wear and to maintain the arcuate form of the abrading end.

Our improved device is simple in construction, provides an economical abrading means for the grinding wheel, and is exceptionally effective in truing and dressing grinding wheels,

Having thus fully described our invention, what we claim as new, and desire to secure by Letters Patent, is: r

1. In mechanism for truing and dressing composite grinding wheels, the combination with the grinding wheel, of a composite abrading bar having a texture harder and coarser than the texture of said grinding wheel, means for pivotally supporting said abrading bar for presenting its end to said grinding wheel, said presented end being of arcuate form, and means whereby to oscillate said abrading bar on its pivot for moving the arcuate end of said abrading tool across the grinding wheel while in contact with the grinding wheel causing it to travers-e the grinding surface of said grinding wheel in opposite directions in arcuate paths to thereby clean and sharpen said grinding surface.

2. In mechanism for truing and dressing composite grinding wheels, the combination with the grinding wheel, of a composite abrading bar having a texture harder and coarser than the texture of said grinding wheel. means for pivotally supporting said abrading bar for presenting its end to said grinding wheel, said presented end being of arcnate form, and automatic means whereby to automatically oscillate said abrading bar on its pivot for moving the arcuate end of said abrading tool across the grinding wheel in contact with the grinding wheel for causing it to traverse the grinding surface of said grinding wheel in opposite directions in arc uate paths to thereby-clean and sharpen said grinding surface.

3. In mechanism for truing and dressing composite grinding wheels, the combination with the grinding wheel, of a composite abrading bar having an arcuate abrading end and having a texture harder and coarser than the texture of said grinding wheel, means for pivotally supporting said abrading bar for presentin said arcuate end to said grinding wheel, automatic means for oscillating said abrading bar for causing said arcuate end to traverse the grinding surface of said grinding wheel in opposite directions for rotating said arcuate end of said abrading bar across the grinding face of the grind'ng wheel in opposite directions in contact with said grinding surface to thereby clean and sharpen said grinding surface, and means whereby to position said abrading bar out of range with said grinding wheel.

1. In mechanism for truing and dressing composite grinding wheels, the combination with the grinding wheel, of a composite abrading bar of substantially large cross-section and having a texture harder and coarser than the texture of said grinding wheel and of such tenacity as to enable a protruding end of said abrading bar to unsupportingly withstand the lateral stresses of its abrading action on said grinding wheel, means for re leasably supporting said abrading bar in manner to provide such protruding abrading end and comprising means for endwise adjustment of said abrading bar with relation to the grinding surface of said grinding wheel. said abrading bar provided with an arcuate end abrading face arranged for abrading engagement with said grinding wheel, and means for pivotally supporting said supporting means whereby to oscillate said arcuate end abrading face of said abrad' ing bar for causing its arcuate end to traverse said grinding surface of said grinding wheel in opposite directions for cleaning and sharpening said grinding surface.

5. In. mechanism for truing and dressing composite grinding wheels, the combination of a composite abrading bar having a texture harder and coarser than the texture of said grinding wheel and being of substantially large cross-section, aholder for said abrading bar arranged for holding said abrading bar with the end of said abrading bar protruding therefrom toward said grinding wheel. said abrading bar being of substantially large cross-section and of such tenacity asto enable said protruding end of said abrading bar to unsupportin gly withstand the lateral stresses of its abrading action on said grinding wheel, said abrading bar provided with an arcuate end abrading face coacting with a iu-o said inding Wheel, a bracket, means for adjustaly supporting said bracket on the Worksupporting table of the grinding machine; a stub on said bracket, means pivoting'said holder to said stub, means adjustably positioning said stub on said bracket for adjustment of said abrading bar With relation to the grinding surface of said grinding Wheel,"a motor on said bracket, a-reciproca-ting llllk between said motor and said holder, conlink so located as to swing said holder'on its pivot for positioning said abrading bar out of range With said grinding wheel.

'In testimony whereof, we have hereunto signed our-names.

FERDINAND J. HoHNHoRsT. FERDINAND J. KROEGER. 

